Injection moulding of plastics articles

Abstract

An injection moulding apparatus includes an openable mould ( 1, 3 ) having a plurality of cavities for injection moulding articles ( 6 ), and, disposed below the mould cavities, a plurality of post cooling cavities ( 13 ) into which in use released injection moulded articles ( 6 ) may pass at least partially under gravity when released from the mould cavities.

The invention claimed is: 
     
       1. An injection moulding apparatus comprising:
 an openable mould having a plurality of cavities and a plurality of mould cores extending generally horizontally, for injection moulding articles having a generally horizontal orientation, 
 a plurality of substantially vertically directed post cooling cavities, disposed below said mould cavities and into which in use released injection moulded articles may pass at least partially under gravity when released from said mould cavities and ejected from said mould cores, and 
 an array of chutes having upper ends to receive respective moulded articles released from said mould cavities, and lower ends to discharge the articles into selected post-cooling cavities, 
 wherein, in use, said chutes receive said injection moulded articles upon release from said mould cores and change the alignment of each injection moulded article to a generally vertical orientation to pass into a respective post-cooling cavity, and 
 wherein said mould cavities are arranged in rows and said array of chutes is stepped so that the upper ends thereof are in substantially the same relative orientation to each of the respective mould cavities. 
 
     
     
       2. An injection moulding apparatus according to  claim 1 , wherein said plurality of chutes is movable together between an upper, receiving position and a lower, delivery position. 
     
     
       3. An injection moulding apparatus according to  claim 2 , wherein each of said chutes includes a releasable retaining element for retaining an article at least partially in said chutes, but releasable to allow said retained articles to drop into respective post-cooling cavities. 
     
     
       4. An injection moulding apparatus according to  claim 3 , wherein said releasable retaining elements are configured to be released by vertical movement of said chutes as said chutes approach or arrive at said lower, delivery position. 
     
     
       5. An injection moulding apparatus according to  claim 1 , which includes gripping elements for gripping cooled articles in said post-cooling cavities, withdrawing them from said cavities and releasing said articles. 
     
     
       6. An injection moulding apparatus according to  claim 5 , wherein said gripping elements are mounted at or adjacent the chutes and movable vertically between a position in which they are operable to grip in use respective upper portions of the cooled articles in the post-cooling cavities, and a position in which the gripped articles are lifted clear of the cavities. 
     
     
       7. An injection moulding apparatus according to  claim 5 , wherein said moulded articles are of hollow tubular form open at one end and closed at the other, and each said gripper element includes an elongate element for engaging the inner surface of the closed end of the article in use. 
     
     
       8. An injection moulding apparatus according to  claim 7 , wherein said elongate elements are moveable relative to the gripper elements and biased downwardly relative thereto, to apply a downward force to the articles in said post-cooling cavities. 
     
     
       9. An injection moulding apparatus according to  claim 7 , wherein at least some of the gripper elements and/or the elongate elements are cooled, thereby in use to extract heat from said article. 
     
     
       10. An injection moulding apparatus according to  claim 1 , wherein said post-cooling cavities are disposed in one or more arrays in a cooling block. 
     
     
       11. An injection moulding apparatus according to  claim 10 , wherein the number of post-cooling cavities is an integral multiple of the number of mould cavities, thereby to allow in use said articles to remain in said cooling cavities for a duration generally equivalent to a corresponding multiple of the moulding process cycle duration. 
     
     
       12. An injection moulding apparatus according to  claim 10 , wherein a cooling arrangement is provided for said cooling block. 
     
     
       13. An injection moulding apparatus according to  claim 1 , wherein said cooling block is movable horizontally to align said chutes with selected post-cooling cavities. 
     
     
       14. A method of injection moulding comprising:
 providing an openable injection mould having a plurality of cavities and a plurality of mould cores extending substantially horizontally, for injection moulding articles for injection moulding articles having a substantially horizontal orientation, the cavities being arranged in rows; 
 providing an array of chutes having upper ends positionable to receive respective articles released from said mould cavities and lower ends positionable to discharge the articles, said upper ends being stepped so that they are in substantially the same relative orientation to each of the respective mould cavities; 
 moulding a plurality of articles in said cavities; 
 opening said mould to release said injection moulded articles on said mould cores, 
 ejecting said injection moulded articles from said mould cores, 
 allowing said ejected injection moulded articles to pass at least partially under gravity into respective, substantially vertical post cooling cavities disposed generally below said mould, 
 wherein, each ejected moulded article falls into a respective chute that changes an alignment of each injection moulded article into a substantially vertical orientation to pass into a respective post-cooling cavity.